Bruxism scores obtained from a new plastic laminated-nightguard (designed to be scored by area and level ground away) will be used to discriminate between a population of bruxists and non-bruxists. In the first proposed experiment, the short and long term impact on bruxism scores of a reportedly effective behavior modification technique of bruxism control (massed practice) will be studied employing a homogeneous group of bruxists in wich occlusal adjustment is indicated but not performed. The results will be compared with the impact of occlusal adjustment on a comparable group of subjects. The experimental design also includes two control groups, one comprised of non-bruxists, the other comprised of bruxists for whom occlusal adjustment is indicated but not performed. In the second proposed experiment, the short and long term impact on bruxism scores of six behavior modification techniques will be compared. Six experimental groups and one control group will be comprised of bruxists for whom occlusal adjustment is either not indicated or indicated and performed but continue to brux. Behavior modification techniques to be compared include Massed Practice, Passive Avoidance, Aversive Conditioning, Development of Depressor Muscles, Relaxation training with Systematic Desensitization and Assertive Training. Correlations will be examined between personality variables and effectiveness of specific behavior modification techniques. The number of subjects planned for Experiment 1 is 20 per group, for Experiment 2, 10 per group. The proposed research is designed to provide objective data on the necessity and sufficiency of occlusal adjustment in bruxism control, the relative effectiveness of behavioral methods of bruxism control and the future application of specific treatments to individuals with specific behavioral clusters (personalities).